Oil-burner construction



Dec. 2, 1930. H. w. GASTON 1 ,783,567

OIL BURNER CONSTRUCTION Filed Jan. 4, 1927 8 Sheets-Sheet 1 IIH' 2 i". I

Dec. 2, 1930. H. w. GASTON OIL BURNER CONSTRUCTION Filed Jan. 4. 1927 Hum M 8 Sheets-Sheet 2 IN VEN TOR.

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OIL BURNER CONSTRUCTION Filed Jan. 4, 1927 a sfieets-sheet 6 1 EN TOR.

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OIL BdRNER CONSTRUCTION Filed Jan. 4, 1927 a sbogts-sheet 7 )1 uwzvrox x ATTORNEY.

Dec. 2, 1930. w, GASTON 1,783,567

OIL BURNER CONSTRUCTION Filed Jan. 4, 1927 8 Shuts-Sheet 8 VEN TOR.

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Patented Dec. 2, 1930 v UNITED STATES.

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NT oF FICE HARRY WILIBUR GASTON, or NEW ROCHELLE, NEW YORK, TASSIGNIOR 'ro' BOYCE AU'IO- MATIC OIL BUBNER'CORPORATION, or NEW YORK, N. Y., A conrom'rron or NEW YORK OIL-BURNER CONSTRUCTION Application filed January 4, 1927. Serial No. 158,849.

This invention relates generally to the construction of oil burners and more particularly to an oil burner capable of use with household or domestic furnaces of existing types. 7

It is well known that oil burners for house hold furnaces-are rapidly coming into use although the types of burners heretofore produced have not reached/a wholly satisfactory stage of development and are characterized by various objectionable features. For example, there is a general type of burner in which a blower supplies air to the combustion chamber in such volume as to insure the complete combustion of the atomized oil which is supplied without previous admixture with air and therefore burns with a yellow flame. The yellow flame will, of course, deposit soot on-any surface of moderate temperature with which it comes in contact so that it is necessary tolprevent contact of the flame with any'portion of the 'wall surface of the combustion chamber and to provide fire clay or metal refractories, or brick chambers for the combustion flames.

The excess quantity of air required to produce only moderately perfect combustion under the conditions'named results in the production of considerable noise in the blower operation through which the air is blown into the combustion chamber as well as excessive noise-in the combustion chamber itself. In addition, the excess volume of air thus supplied results in'an ineflicient operation of the burner'sinc'e'the excess air interferes with a fully effective transfer of heat units from the flame to the walls of the com-- bustion chamber, and cools'down the flame thereby diminishing its efficiency.

Another type of burner which has gone into relatively extensive .use includes the forcing'ofoil'vapor under considerable pressure through a small opening at the end of a retort in whichthe oil i's'heated 'to produce oil vapor which issues through the orifice. This type a of burner. produces a blue flame which is, of course, desirable in that itcan directly engage" combustion chamber surfaces without the depos tion of soot thereon. The strucf combustible ture, however, is open to the objection that the small orifice through which the oil vapor must pass is easily clogged, thereby interrupting the operation of the burner..' In addition to the danger which accompanies the use of oil under pressure, the apparatus necessary to produce the requisite'pressure in the oil is relatively expensive. In addition to this, the retort chamber is subject to obstruction through the formation of carbon deposits therein.

Still another type of burner includes a structure in which the air for combustion is blown into the combustion chamber, a pot.- like receptacle being employed to restrict the projection of flame.- vThe character of the flame is in some cases partially blue, dependence being placed upon the heated surfaces engaged by the flame to aid in the combustio of the fuel.

A general object of the present invention is and which will produce a blue'or Bunsen'type' offlame without producing pressure condi tions in the oil supplied to the burner and without the useof refractories or equivalent members. It is also an-object'to produce a flame that may be burned in suspension, or that may be projected against water jacketed surfaces without producing soot.

The invention comprises a burner construction in which provision is made for a mixture of. air and oil (vapor to produce a perfectly gas mixture inadvance of its delivery to the urner proper. By reason of the pre-mixing of air and oil vaporin the proportions best suited to perfect combustion, Isucpeed in producing at the burner the desirable blue flame and without theQaccompanying projection withmore or lessforce of flame v against a refractory or other surface. "The blue flame produced in the improved burner is of'the suspension type and is characterized; by its volume rather than velocity or forcible discharge; This type of flame is ideally suited to the purpose to which it is put in that it can engage the enclosing surfaces. of the combustion chamber and directly impart heat units thereto without the deposition of soot thereon.

These desirable results are obtained by the regulation of the supply of air and oil to the burner in the particular proportions best suited to produce a perfectly combustible gas mixture. The oil is supplied to a vaporizing device mounted closely adjacent the burner wherein itis converted into vapor which rises through the vertically extending vaporizing chamber and passes into a mixing chamber where it is intermixed with preheated air passing into the device from ablower. The mixture of hot oil vapor and heated air thus produced then passes downwardly through a depending burner head to the burner proper which is located at the lower extremity of the burner device. The flame produced at the burner is, as has been pointed out, of the blue type and hot gases evolved therefrom pass up wardly along the depending burner head to produce therein the heated condition best suited to preheat and thoroughly gasify the mixed air and oil vapor before passing through the burner head for combustion. Another feature of the invention resides in the arrangement of structure in such manner that the burner parts are inserted through the ordinary furnace coal supplying door and without disturbance of the existing grate structure in the combustion chamber. This affords the use of the downwardly extending burner head which forms a'useful portion of the invention, as has already been pointed out. I

The structure is simple and inexpensive to construct in that it does not include such elements as oil pumps, compressor units, pressure reducing and regulating valves, diaphragms, ratchets, gears, and other devices which are usually included in burner constructions of the types heretofore known and,

used.

Other features of the invention will be hereinafter referred to.

In the drawings, in which a preferred embodiment of the invention has been selected for illustration: I

Figure 1 is av view in side elevation and partly in vertical section of an oil burner for furnaces embodying the invention;

Figure 2 is a view in side elevation and partly in section of a heater or furnace equipped with an oil burner similar to that shown in Figure 1;

Figure 3 is a view in end elevation of the device shown in Figure 1;

Figure 4 is a plan View of the gas burner shown in Figure 1;

Figure 5 is a view in vertical section and on an enlarged'scale of a detail of the construction shown in Figure 1;

Figure 6 is a pers ective view of the valve structure shown in igure 5;

Figure 7 is a plan view partly in section and on an enlarged scale of the detail of con struction shown in Figurel;

Figure 8 is a sectional view on an enlarged scale taken on the line 88 of Figure 7 Figure 9 is a view in side elevation and partly in vertical section of a detail of structure shown in Figure 1;

Figure 10 is a view in vertical section taken on the line 10-10 of Figure 9;

Figure 11 is a plan view partly in horizontal section and on an enlarged scale taken centrally of the burner head 24;

Figure 12 is a view partly in side elevation and partly in vertical section of the parts shown in Figure 11; Y

Figure 13 is a view in side elevation and partly in vertical section'taken on the line 1313 of Figure 7;

Figure 14 is a view partly in vertical section and partly in side elevation of a magnetic valve structure forming part of the in- Y vention;

Figure 15 is a perspective viewon an en-- larged scale of a calibrated dial plate shown in Figure 13;

Figure 16 is a view in diagrammatic form of a system of electric circuits used in the operation of the device' Referring to the drawings for a more detailed description of the invention, in Figure 1 there is 9. shown an oil burner construction which includes adepending mixing chamber a furnace 13, as is indicated in a general way inFigure 2 of the drawings. The chamber member 11 is attached at 14 to the terminal of a horizontally extending conduit 15 which opens upwardly into the outer end of the chamber structure 11 as is clearly indicated in Figures 1 and 5 of the drawings. The horizontally extending conduit 15 connects at its outer end with a discharge tube 16 of a blower 17 actuated by a suitable electric motor 18 of relatively small size, a motor of one-twentieth horse power having been found suitable for the purpose.

It will be seen that the operation of the blower 17 serves to deliver a current of air through the conduit 15 into the chamber 11, passing into the chamber through a port 19 with which a flap valve 20, formed of lightweight metal, cooperates to prevent any reversal of flow of gas through the port opening 19 into the conduit 15.

Means are also provided for delivering into the chamber 11 oil vapor, the'oil vapor .-and air entering the chamber 11 being intermixed and converted into a combustible gas mixture havin its ingredients proportioned in the relative to form a perfectly com ustible gaseous mix ture. The oil from which vapor is delivered into the chamber 11 passes through a pipe 21 into a vertically extending vaporizing tube 22 which terminates at its lower end in a coil 23 mounted adjacent the burner head 24 carried bv the lower extremity of the chamber The gaseous mixture thus formed is passed downwardly through the depending chamber 10 and is deflectedinto a spiral path of travel by a series of s irally arranged baflle plates 25 which contri ute to the thorough mixing of the air and oil vapor. The thoroughly mixed gaseous fuel thus produced emerges at the lower end of the chamber 10 and through saw cut openings 26 in the burner head 24 where combustion takes place and a blue flame is produced because of the nature of the mixture and the adequate supply of air contained therein.

The blue flame thus produced which is a prominent characteristic of applicants invention is similar to that produced in an ordinary gas stove burner wherein a sufficient supply of air is admitted for admixture with the gas before ignition at the burner openings. The blue flame thus produced, as is well known, perfectly supports combustion so that there is no liberation of carbon with a resulting blackening of vessels against which a flame of this character impinges.

The blue flame thus produced has been heretofore obtained in oil burner constructions only with complicated apparatus which included the supplying of oil under considerable pressure and passing the oil through a closed retort having a small orifice through which the oil vapor issued at high pressure. So far as applicant is aware, he is the first to produce the Bunsen 'or blue flame in which the air for combustion is provided by a blower in the precise proportions needed for adfiixture with oil vapor to produce a gaseousfnixtureof the desired characteristics.

In order to prfiizminarilv heat the burner head 24 and the t iibe 22 with its coil 23, a gas 1 burner 27 is provided which is mounted on the furnace grate structure 28 immediately below the coil 23. A pilot burner 29 is supplied with gas by way of a by-pass pipe 30 which leads from a gas conduit 31 having a magnetically actuated valve 32 which, when opened, supplies gas to the burner 27 to heat the coil 23. The burner 27 is preferably mounted in a. pan-like receptacle 33 which uantities best suited serves to deflect the heat upwardly for more effectively heating the coils 23.

Having now described the structure which is adapted to be placed within the combustion chamber of the furnace, reference will be had to those parts of the mechanism which are mounted externally to the furnace. At 34 is shown a standard on which the blower 17 and motor 18 are arranged to be mounted. A bracket supporting member 35 for the mechanism has a downwardly extending portion 36 adapted to have telescopic relation to the standard 34 and to be held in any desired position of elevation in relation thereto by means of a set screw 37.

The supply of oil to the burner is preferably obtained from a connection at 38 conveniently located beneath the standard 34 and passes through a flexible conduit 39 to a filter or strainer valve 40 and thence through a magnetically actuated valve device 41 and by way of conduit 42 through a chamber 43 in which a float-controlled valve 44 is mounted. It Will be seen that the float controlled valve 44 will operate to shut off the further supply of oil to the chamber 43 when the oil therein has reached a certain predetermined level which is lower than the level of the outlet port 19 (Figure 5) leading from the air su ply conduit 15 into the mixing chamber 11. Oil passes from the valve chamber 43 by way of needle valve 45 through conduits 46 and through a magnetic valvedevice 47 into the oil supply line 21 already referred to. It will be seen that an effective control of the supply of oil to the burner is provided through the two magnetic valves 41 and 47 arranged in series in the line, the float controlled valve 44 and the manually controlled needle valve 45 by means of which a predetermined quantity of oil is permitted to pass into the supply line 21.

' At 48 in the oil supply line is mounted a reservoir or stand pipe which serves to hold such oil as finds its way through the float valve after the magnetic valves have been closed. The reserve or accumulation of oil thus established is utilized to advantage ,when the burner is next set into operation.

be relatively adjusted to produce the desired proportioning of the oil and air to achieve the combustible mixture which is subsequent 1y brought about g the mixing chamber 11. The cooperative adjustment of the two valves can readily be broughtabout by observation of the flame produced by the burn.-

er head 24. When a blue flame is produced, the relative setting of the valves is correct and the valves are permitted to remain in the adjusted positions.

In order to safeguard the structure against an over supply of oil to the burner parts, a bucket 52, Figure 3, is provided in Which surplus oil is fed from a pipe 53 to'operate a switch arm 54 in a known manner to shut off the supply of current to the motor 18 as Well as to close the magnetically actuated valves 41 and 47. The pipe 53 extends to the float valve chamber 43 in order to supply a surplusage of oil to the bucket switch in the event that the float valve should fail to close when the level of oil in the chamber has risen beyond the predetermined level.

. This would obviate the possibility of oil finding its way into the burner structure during an idle period.

Referring to Figure 16, of the drawings, there is shown an electric circuit arrangement by which the control of the operation of the oil burner described is effected. A thermostat 57 located in a room wherein temperature conditions are to be utilized in the control of the burner is connected through the conductor 58 to service line 59. The other side of the thermostat 57 is connected through a conductor 60, pyrometer switch 61, conductor 65, switch 66 turning on the gas in supply line 31, bucket switch 52, conductor 81, and service line 67. Thus one of the things that the thermostat 57 does is to turn on the gas whereupon the burner 27 is lighted by means of the pilot 29. Thermostat 57 also operates further instrumentalities as follows: Current after traversing switch 61, passes through conductor 63 wherein it divides into two parallel circuits, one circuit passing through heating coil 68 for the air supply in conduit 15, mercury switch 75, conductor 73 to line 67; the other circuit passing through time switch 74, mercury switch 75, conductor 73 to line 67. In order to cause the pyrometer switch 61 to break the circuit through the gas supply valve 66, a quantity of heat is required which is greater than that supplied by the gas flame. The heat for this purpose comes from the operation of the oil burner which takes place following the operation of the time switch whose action was initiated at the time the gas burner was turned on.

Meanwhile the heating coil 68 has been supplying heat to the adjacent parts of the air supply pipe 15, with the result that at the same time that the oil-burner parts are heated, the air supplying parts are also heated in order that heated air will be supplied to the mixing chamber 11 when the vaporizing operation begins. This arrangement obviates the condensing of oil vapor such as would result from the introduction into the burner parts of cold air.

In order to assist the gas burner structure in the heating up of the oil burner parts in a desirably brief interval of time, the oil burner structure includes an internal tubular member 70 which extends throughout the vertical length thereof and has its open lower end 71 located immediately above an upward extension 72 of the burner structure. The result is that a considerable quantity of heat is supplied to the tubular member 70 which is preferably formed of metal having relatively high heat conductive properties. The result is that the bafiie members 25, which are directly connected to the wall of the tube 70, are quickly heated, thereby insuring the immediate heating of the intermixed oil vapor and air which is directed downwardly through the burner tube 10 when the blower is set into operation. Thus the heating of the oil burner parts by the operation of the gas burner 27 and the heating of the air supply passages through the use of the heating coil 68results in the effective operation of the oil burner from the beginning of the supply of air and oil thereto.

The putting into operation of the oil burner will now be described. As stated, time switch 74 has been placed in operation simultaneously with heating coil 68. When heat has been supplied thereto for a predetermined interval of time, for example, four minutes, the switch operates to actuate a tiltable mercury switch 75 and to cause the switch to move to a position to close the circuit through motor 18 and the magnetic oil control valves 47 and 41. The circuit thus established includes service line 59, conductor 58, room thermostat 57, conductor 60, conductor 76, valves 47 and 41, conductor 77, switch 75, motor 18, bucket switch 52, conductor 81 and service line 67. The operation of the switch 74 will be apparent from Figure 10 in which 740 represents a heating coil, 741 insulation therefor, 742 a coil of thermostatic material arranged so that upon being heated by the coil 741, it will change its shape so as to rotate spindle 743, carrying mercury switch 75 and thereby operate same.

The setting of the motor 18 into operation, of course, starts the actuation of the blower 17 so that air is supplied through the line 15 to the chamber 11 of the burner structure. At the same time the opening of the magneticallv controlled valves 41 and 47 permits the flow of oil into the supply line 21 and thence into the vaporizing tube 22. The burner thereupon begins to function and oil vapor is delivered from the upper end of the vaporizing tube 22 into the chamber 11 for admixture therein with the heated air entering the chamber from the supply pipe 15. 7

As thus far described both the gas burner 27 and the oil burner, are in operation. Shortly after this event, however, the increased heat operates the pyrometer switch 61 to break the circuit through switch 66 whereby the gas to burner 27 is'cut ofl.

ion

In order to maintain the mercury switch 75 in circuit closing relation to the motor 18, a vane member 82 is so related to the flow of air through the valve chamber 83 that the kinetic energy and pressure of air against the vane member holds the mercury switch in the tilted position required to maintain the circuit in closed condition. It will be clear that upon failure of the air supply from the blower 17 from any cause, the vane will settle back to the vertical position shown in Figure 9 of the drawings in which the switch 75 assumes a circuit breaking relation with respect to the contact points 84. The vane member is provided at its lower extremity with a weight 85 to insure the tilting of the switch 75 to circuit breaking position upon failure of the air supply from the blower 17. It will be seen that the vane member 82 occupies substantially one half of the cross sectional area of the chamber 83 which is a proximately equal to the cross section of tEe air supply line 15. The upper half of the chamber 82 is closed by a plate 86 clearly shown in Figures 9 and 10 of the drawings.

It will be seen that the circuit control described provides adequate safeguards against any 'contingency that might arise in the operation of the burner. It will also be noted that a failure of the supply of air from the blower 17 will bring about an actuation of the mercury switch 75 to cut off the supply of current to the motor and also to close the oil supply valves 41 and 47. In addition, an over supply of oil to the pipe 15 for any cause would result in the operation of the bucket switch 52 to bring about the breaking of the circuit through the motor 18 and also through the oil supply valves 41 and 47. It will also be seen that the rise of temperature in the room containing the thermostat 57 will result in the breaking of the circuit through the oil supply valves 41 and 47 as well as through the motor 18, thereby bringing about a cessation of operation of the burner until the temperature has been reduced in the vicinity of the thermostat 57.

The provision of the flap valve 20 at the point of juncture of the air supply pipe 15 and the chamber 11 prevents the outward flow through the supply pipe of fumes when the burner is not in operation, as will be clearly understood. The valve has a very lightweight construction in order to provide the least possible retardation of the flow ofair from the pipe 15 into the mixing chamber 11.

In order to assure the clearing of oil from the supply passage or pipe 21 following the shutting off of current to the motor, a fly wheel construction 87 is embodied in the blower construction to provide for the operation of the blower for a brief interval following the shutting off of the supply of current thereto. This will insure the supply of sufficient air to carry on the combustion until the supply of oil vapor has ceased.

It will be seen that the flow of oil through the oil supply pipe 21 takes place wholly by gravity, there being no pressure produced in the oil in order to deliver any to the burner structure. It will be clear that-the storage reservoir or tank for the oil supply will be located at a level higher than'that of the burner device in order to insure the delivery of oil to the float chamber 43:

Referring again to the operation of the vaporizing tube 22, I find that the supply of oil to the vertical vaporizing tube 22 at a point near its upper end results in an effective vaporizing of the oil without the undesirable production of carbon in the generator tube. The oil entering from the supply pipe 21 clings to the inner surfaces of the vaporizer tube as it flows downwardly into the hotter portions of the vaporizer tube in the coiled extremity 23. The conversion of the oil into vapor ta es place in a progressively increasing degree as the oil flows downwardly into the hotter portions of the tube, the vapor immediately rising and flowing into the chamber 11 where the intermixing of heated air from the conduit 15 with the oil vapor begins. It will be clear that the vaporizing tube is comparatively cool at the point of entrance of the oil with a gradually increasing temperature toward the dead end of the coil 23. With this arrangement gasification takes place without the accompanying format on of carbon because the immediate eliminat on of vapor as it is formed prevents overheating which would tend to crack the oil and depos t carbon on the walls of the chamber. In this particular the form of vaporizer employed is greatly superior to the retorts characteristic of burner constructions heretofore known and used.

As has already been pointed out, the flame produced at the burner head 24 is of the blue or Bunsen type and, as a result of the blower action, the flame is projected sufficiently through the annular wall of the burner to cause the annular wall of flame to assume a substantially horizontal position. This is particularly effective in directly heating the surrounding surfaces of the water reservo r of the furnace and imparting heat thereto. In addition, the slightly outward projection of the flame, which is thus produced, prevents the direct engagement of flame with the walls of the mixing tube 10, thereby preventingthe deterioration of the tube from overheating. It will be seen that by the use of a burner head adjusted to operate with a combustible gas characterized by volume rather than velocity, the reduction of noise is accomplished and an eflicient operation of the apparatus obtained.

I may make use of a directing member 88 occupying a substantially enclosing relation to the mixing tube 10 and having a conical formation which serves to collect or concentrate heated air and apply it to effectively heat the walls of the mixingchamber 10.

In order to prevent the access of excess air through the ash pit portion of the furnace, a bed of ashes 89 may be placed in position on the grate structure 28 in enclosing relation to the pan-like member 33 which houses the gas burner 27, the pan serving to prevent the ashes from interfering with the burner.

The gas burner structure may be supported on a rod 90 vertically adjustable in a tripod standard 91, the rod as well as the mixing tube of the starting gas burner passing between the grate bars of the furnace.

It will be noted that the oil supply pipe 21 is provided with a peak or high point substantially coincident with the point where the pipe passes into the body of the furnace. This structural arrangement provides for the draining of only a ortion of the length of the oil supply line into the vaporizing tube following the stopping of the burner operation. This feature materially assists in quickly checking the supply of oil to theburner when the operation of the burner has been stopped. 1

It will be seen that the gas burner structure which is employed in initially setting the oil burner into operation is of the blue flame type ordinarily used with gas stoves such as are used in household kitchens. By using a gas burner of this type, characterized by the inclusion of a mixing tube 92, the starting gas burner, as well as the oil burner proper, opcrates with a sootless and eflicient blue flame.

The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and expressions, of excluding any mechanical equivalents of the features shown and described, or portions thereof, but recognize that various structural modifications are possible within the scope of the invention claimed.

What I claim is:

1. In an oil burner construction, a blower for supplying air to the burner in regulated quantities, a conduit for the air supplied by the blower arranged to extend through the fuel supply door of a furnace, a mixing chamber occupying a downwardly projecting position from the end of the an su ply conduit extending into the furnace, a urner head mounted on the lower extremity of the mixing chamber, a closed ended vaporizing tube occupying a vertically extending position adjacent the mixing chamber such that said tube is subject to a progressively higher temperature along the length thereof, and means for supplying a'regulated quantity of oil by gravit to the upper portion of the vaporizing tu e, said vaporizing tube opening at its upper end into the end portion of the air supply conduit adjacent the mixing chamber, whereby oil vapor will enter the air stream and pass through the mixing chamber therewith to produce a gaseous mixture which will burn with a blue flame, said gaseous mixture passing from the supply chamber to the burner head for combustion.

ber to provide a gaseous mixture at the burner head at the lower end of the mixing chamber which will burn with a blue flame.

3. In an oil burner construction for household furnaces, a blower for supplying air to the burner, means for supporting the blower at an elevation substantially. level with the fuel supply door, a conduit extending from the blower through the fuel supply door of the furnace, an elongated mixing chamber occupying a dependin position from the inner end of the air suppTy conduit, said mixing chamber being provided with a burner head at its lower end, a closed ended vaporizing tube occupying a vertically extending position adjacent the burner head, means for supplying oil by gravity to an upper portion of said vaporizing tube, said vaporizing tube opening into said air supply conduit adjacent the upper end of said mixing chamber, whereby oil vapor and air will pass into the mixing chamber to be intermixed therein and provide a gaseous mixture which will burn at the burner head with a blue flame.

4. In an oil burner construction for household furnaces having a combustion chamber,

lull

Ill

ing chamber and opening at its upper end.

"into the air supply conduit, an oil supply pipe extending through the fuel supply 'door of the furnace and opening into said vaporizer tube, a float valve arranged to control the flow of oil through said oil supply pipe, and a pair of magnetically actuated valves mounted in said oil supply pipe one on either side of said float controlled valve, and thermostatic means for controlling said magnetically actuated valves.

5. In an oil burner construction for house hold furnaces, a vertically disposed mixing chamber adapted to be mounted in the combustion chamber of a furnace, a burner head mounted at the lower end of the mixing chamber, means for supplying intermixed air and oil vapor to the upper end of the mixing chamber, a gas burner mounted beneath the burner head to heat the parts preliminary to an oil burning operation, and an 0 en ended tube extending vertically through t e mixing chamber permitting the flow of hot roducts of combustion therethrough, where y heat produced by the gas burner will eifectively raise the temperature of the mixing chamber.

6. In an oil burner construction for household furnaces, a mixing chamber mounted in said furnace, a burner connected to said mixing chamber, an air supply conduit connected to said mixing chamber, a vaporizer chamber mounted adjacent said burner and opening into said air .sup ly conduit, means for supplying oil to said vaporizer chamber, a blower for causing air to flow through said air supply conduit, a heating coil mounted in said air supply conduit in position to heat said conduit for preliminarily heating the air fed therethrough, and temperature controlled means for cuttlng off current to said heating coil upon a rise of temperature in said conduit following the setting of the burner into operation.

7. In an oil burner construction for furnaces having a combustion chamber, a mixing chamber mounted in the furnace an air suply conduit connected to the mixing chamer, a blower for causing air to flow through the air supply conduit to the mixing chamher, a vaporizin device mounted adjacent the mixing cham er, an oil supply pipe connected to the vaporizing device, said vaporizing device opening into said air supply con duit, a float controlled valve mounted in said air supply pipe, a pair of electromagnetically controlled valves one mounted in said air supply line on either side of said float controlled valve, and a manually adjustable valve mounted in said oil supply pipe between said electromagnetically controlled valves.

8. In an oil burner construction for furnaces, an oil supply pipe leading into the furnace, a float controlled valve mounted in said oil supply line, a manually adjustable valve mounted in said oil supply line between said float controlled valve and the burner, an electromagnetically controlled valve mounted in said oil supply line between the manually adjustable valve and the burner, and a reservoir mounted in said oil supply line between said manually adjustable valve and said. electroma etically controlled valve.

9. In an oil urner construction for household furnaces, an oil burner mounted in the combustion chamber of a furnace, a gas burner mounted beneath the oil burner, an electromagnetically actuated valve arranged to control the supply of gas to the gas burner,

a room thermostat arranged to open the valve to sulipl gas to the burner when the temperature alis to a predetermined degree, and a thermostat independent of saidroom thermostat responsive to a rise of temperature in the oilburner structure for cutting oil the supply of gas to the gas burner when the oil burner has been set into operation.

10. In an oil burner construction for household furnaces, an oil burner adapted to be mounted in the furnace, a motor actuated blower for supplying air to the burner, an oil pipe for supplying oil to the burner, an electromagnetically actuated valve in said oil supply pipe, a starting gas burner mounted beneath the oil burner, a timing device set into operation when the starting gas burner is operated, a tiltable mercury switch adapted to be actuated by said timing device, said tiltable switch serving to open and close circuits through said motor and said electromagnetically actuated valve, and a member responsive to the flow of air supplied by the motor for maintaining the switch in circuit closing position while air is flowing from the blower.

11. The method of vaporizing .oil for oil burners which consists in feeding oil in a more or less thin film through a closed ended tube and subjecting said tube to a progressively increasing degree of heat along the length thereof, allowing the produced vapors to escape through said tube in a direction opposite to the flow of oil therein substantially as such vapors are generated, mixing such escaped vapors with air, and then progressively heating the mixture.

12. In an oil burner, a vertically extending mixing chamber adapted to depend into the fire box of a household furnace, said mixing chamber terminating in a burner head, said head being hollow and provided with a multi plicity of vertical, narrowly spaced slots extending the height of the head and spaced along the periphery thereof, and causing the flame to extend substantially continuously around said head.

i 13. In an oil burner construction for household furnaces, a burner having a burner head, a closed ended vaporizing tube depending into proximity of said burner head, and occupymg such a position with relation to said burner that the lower portion of the tube receives the highest temperature, whereas the upper portion of the tube is at a much'lower temperature, and the intermediate portion is subjected to a rogressively increasing temperature in the direction of the lower end thereof, means for admitting liquid oil to the upper portion of the tube and means for talcin" off the produced vapor at the top of said is permitted substantially as t ey are generated and means for intermixin the oil ,vapor and air to produce a combustib e mixture.

tube, whereby the escape of va ors therefrom 14. In an oil burner construction for house- 7 hold furnaces, a burner having a burner head,

a closed ended vaporizing tube depending into proximity of said burner head, and occupying such a position with relation to said burner that the lower portion of the tube receives the highest temperature, Whereas the upper portion of the tube is at a much lower temperature, and the intermediate portion is subjected to a progressively increasing temperature in the direction of the lower end thereof, a gravity feed for admitting liquid oil to the upper portion of the tube and means for taking ofi the produced vapor at the top of said tube, whereby the escape of vapors therefrom is permitted substantially as they are generated and means for intermixing the oil vapor and air to produce a combustible mixture.

15. In an oil burner construction for household furnaces, a burner having a burner head,

a closed ended vaporizing tube depending into proximity of said burner head, and occupylng such a position with relation to said burner that the lower portion of the tube receives the highest temperature, whereas the upper portion of the tube is at a much lower temperature, and the intermediate portion is subjected to a progressively increasing temperature in the direction of the lower end thereof, means for admitting liquid oil to the upper portion of the tube, a conduit for sup plying air to said burner and having communication withthe top of said vaporizing tube whereby said vapors leave said tube sub stantially as they are generated and are added to the air supply to form a combustible mixture.

HARRY WILBUR GASTON. 

